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Key Points Inclisiran for LDL cholesterol reduction was analyzed post hoc in patients with CKD. Mean percentage LDL cholesterol reduction from baseline was around 50% regardless of eGFR in phase 3 trials. Inclisiran showed sustained and effective LDL cholesterol–lowering in patients across various levels of eGFR values, without new safety findings. Background Lowering LDL cholesterol reduces the risk of atherosclerotic cardiovascular disease in patients with CKD. The efficacy and safety of inclisiran versus placebo in patients without and with CKD were investigated in a post hoc pooled analysis of three phase 3 trials (ORION-9, ORION-10, and ORION-11). Methods Patients with heterozygous familial hypercholesterolemia, atherosclerotic cardiovascular disease or its risk equivalent, and elevated LDL cholesterol were randomized 1:1 to subcutaneous inclisiran or placebo on days 1 and 90 and every 6 months thereafter for 540 days. Patients were stratified based on baseline eGFR (by CKD Epidemiology Collaboration equation): ≥90, 60 to <90, 45 to <60, and 15 to <45 ml/min per 1.73 m 2 . Coprimary end points were percentage change in LDL cholesterol at day 510 and time-adjusted percentage change after day 90 and through day 540. Safety was also evaluated. Results Of 3660 patients, 1610 (44%) had eGFR ≥90, 1608 (44%) 60 to <90, 300 (8%) 45 to <60, and 142 (4%) 15 to <45 ml/min per 1.73 m 2 . The mean (95% confidence interval) placebo-corrected percentage changes in LDL cholesterol from baseline at day 510 in patients with eGFR ≥90, 60 to <90, 45 to <60, and 15 to <45 ml/min per 1.73 m 2 were −49.9% (−53.2 to −46.6), −51.2% (−54.4 to −48.0), −54.7% (−62.5 to −47.0), and −44.7% (−57.6 to −31.8), respectively ( P < 0.001); the corresponding mean (95% confidence interval) time-adjusted placebo-corrected percentage changes in LDL cholesterol from baseline after day 90 through day 540 were −48.4% (−50.8 to −46.1), −51.8% (−54.2 to −49.4), −55.6% (−61.0 to −50.2), and −50.4% (−59.3 to −41.5; each P < 0.001). Significant decreases in total cholesterol, apolipoprotein B, non-HDL cholesterol, and lipoprotein(a) occurred in all eGFR groups. Inclisiran was well tolerated without new safety findings. Conclusions Inclisiran demonstrated sustained and effective LDL cholesterol reduction in patients with or at risk of atherosclerotic cardiovascular disease, regardless of baseline eGFR as low as 15 ml/min per 1.73 m 2 , without new safety findings. Clinical Trial registry name and registration number: ClinicalTrials.gov, ORION-9 (NCT03397121), ORION-10 (NCT03399370), and ORION-11 (NCT03400800).

Background: Colorectal cancer (CRC) is the second leading cause of cancer-related mortality worldwide, accounting for approximately 10% of all cancer cases. Despite the proven effectiveness of conventional screening modalities such as colonoscopy and fecal immunochemical testing (FIT), their invasive nature, high cost, and limited patient compliance hinder widespread adoption. Recent advancements in artificial intelligence (AI) and bowel sound-based signal processing have enabled non-invasive approaches for gastrointestinal diagnostics. Among these, bowel sound analysis—historically considered subjective—has reemerged as a promising biomarker using digital auscultation and machine learning. Objective: This review explores the potential of AI-powered bowel sound analytics for early detection, screening, and characterization of colorectal cancer. It aims to assess current methodologies, summarize reported performance metrics, and highlight translational opportunities and challenges in clinical implementation. Methods: A narrative review was conducted across PubMed, Scopus, Embase, and Cochrane databases using the terms colorectal cancer, bowel sounds, phonoenterography, artificial intelligence, and non-invasive diagnosis. Eligible studies involving human bowel sound-based recordings, AI-based sound analysis, or machine learning applications in gastrointestinal pathology were reviewed for study design, signal acquisition methods, AI model architecture, and diagnostic accuracy. Results: Across studies using convolutional neural networks (CNNs), gradient boosting, and transformer-based models, reported diagnostic accuracies ranged from 88% to 96%. Area under the curve (AUC) values were ≥0.83, with F1 scores between 0.71 and 0.85 for bowel sound classification. In CRC-specific frameworks such as BowelRCNN, AI models successfully differentiate abnormal bowel sound intervals and spectral patterns associated with tumor-related motility disturbances and partial obstruction. Distinct bowel sound-based signatures—such as prolonged sound-to-sound intervals and high-pitched “tinkling” proximal to lesions—demonstrate the physiological basis for CRC detection through bowel sound-based biomarkers. Conclusions: AI-driven bowel sound analysis represents an emerging, exploratory research direction rather than a validated colorectal cancer screening modality. While early studies demonstrate physiological plausibility and technical feasibility, no large-scale, CRC-specific validation studies currently establish sensitivity, specificity, PPV, or NPV for cancer detection. Accordingly, bowel sound analytics should be viewed as hypothesis-generating and potentially complementary to established screening tools, rather than a near-term alternative to validated modalities such as FIT, multitarget stool DNA testing, or colonoscopy.

Abstract Background We aimed to describe the real-world durability of clinical and endoscopic outcomes of upadacitinib (UPA) in ulcerative colitis (UC). Methods We retrospectively analyzed an ongoing multi-center cohort of UC patients(pts) in the United States who were started on UPA for active disease. Primary outcome was clinical remission at 1yr assessed by partial Mayo score(pMS)(resolution of all UC related symptoms and physician global assessment). Secondary outcomes assessed at various timepoints, including after re-escalation, included clinical response(&gt;50%reduction in symptoms utilizing the pMS), endoscopic response (Mayo endoscopic score≤1or absence of erosions/ulcerations) and histological remission(defined as normal or chronic inactive). Durable secondary outcomes achieved at both 6months and at 1yr and beyond were also assessed. Descriptive statistics were performed. Adverse events(AEs) investigated included cardiovascular events and herpes zoster (HZ). Results 416pts were included(Table 1) with median values for age at initiation of36.00yrs(range27-48), disease duration7.00yrs(range3-14)and follow-up 993days(IQR,672-1103), with206(49.52%)with follow-up at 1yr or beyond. Of these, 66.1%had extensive colitis. Induction duration was8wks in 86.5%and16wks in 4.8 %(20/416). Most received an induction dose of45mg(97.1%)and maintenance dose of30mg(85.8%). Among the evaluable population at1yr and beyond, 62.5%(45/80)were in clinical remission, 75.9%(22/29)in endoscopic response with58.6%(17/29) in remission and66.6%(20/30)in histological remission. At 6months, clinical remission was51.6%(42/93), endoscopic response was 75%(24/32) of which43.75%(14/32)were in remission and histologic remission was seen in 40.8%(20/49).Durable secondary outcomes of clinical remission were seen in 71.4%(30/42), endoscopic improvement in 45.8%(11/24), and histologic remission in35%(7/20). Re-escalation to 45mg occurred in 35pts, of which48.6%(17/35)were re-escalated due to incomplete induction clinical response with all achieving response(11 in remission). The rest(18/35)were re-escalated for clinical relapse after initial remission where72.2%(13/18)were able to recapture remission. After re-escalation,54.3%(19/35)continued on 45mg daily. AEs were reported in12.7%with HZ in 7pts(2.1%). One pt aged53yrs had an episode of TIA after 1yr on UPA at 15mg, without pre-existing cardiovascular risk factors and UPA use is ongoing at the same dose. There were no reported episodes of worsening of pre-existing cardiovascular disease or DVT/PE. Conclusion UPA is durably effective and safe in a real-world clinical setting with re-escalation to 45mg capturing response in a majority of the pts. Ongoing recruitment will provide further evidence on long term effectiveness and safety. Conflict of interest: Ms. Huang, Katherine: No conflict of interest Chandnani, Arun: No conflict of interest Samaan, Sami: None Tan, Tingyi: I have no conflict of interests to declare. Ramesh, Prajith Raj: None Conlon, Caroline: No conflict of interest Klein, Jeremy: None Reddy, Nikhil: No conflict of interest Ayoub, Malek: None Cervantes Limon, Gabriela: none Myers, Melissa: None Bucaram, Martha: No conflict of interest Lieto, Stephen: No conflict of interest Scalzo, Nicholas: No conflict of interest Cohen, Benjamin: Abbvie - consulting and speaking ALPCO - consulting J & J Innovative Medicine - consulting Takeda - consulting and speaking Emmes Biopharma Services LLC - DSMB Pfizer - consulting Mohamed, Islam: nothing to declare Ciorba, Matthew: Advisory Board: Janssen, AbbVie, Pfizer, Geneoscopy Consulting: Janssen, AbbVie, Pfizer, Geneoscopy Grant contracts: Janssen, Pfizer, Incyte Shukla, Richa: Speakers bureau - Abbvie and Lilly Wright, Michael: None Xu, An Tao: No conflict of interest Chowla, Navreet: No conflict of interest Ogholikhan, Sina: Abbvie Medical Director Kujawski, Michelle: Abbvie Scientific Director Dulaney, David: Speaker bureau - Regeneron Speaker bureau - Sanofi Speaker bureau - Takeda Speaker bureau - Eli Lilly Fenster, Marc: none Benson, Caroline: No conflict of interest Alhobayb, Tamara: No conflict of interest Berinstein, Jeffrey: No conflict of interest Shivashankar, Raina: Abbvie and BMS - speaker bureau Janssen and Celltrion - grant for IBD fellowship funding Pfizer - consultant Bishu, Shrinivas: None Patel, Anish: speaker: abbvie, J & J, Lilly, BMS, Pfizer, Phathom, Takeda consultant: abbvie Ungaro, Ryan: Personal Fees: AbbVie, Bristol Myers Squibb, Genentech, Lilly, Pfizer, Janssen, Takeda Johnson, Amanda: Research grant: Abbvie, Spyre Therapeutics Pekow, Joel R.: CVS Health - Consulting Abbvie, Eli Lilly, Pfizer, Johnson and Johnson - Stocks Yarur, Andres: Personal Fees: Consultant for Takeda, Pfizer, Roche, Merck, Abbvie, Eli Lilly. Bristol Myers Squibb, Celltrion, Johnson and Johnson. Deepak, Parakkal: Parakkal Deepak has received research support under a sponsored research agreement unrelated to the data in the abstract from AbbVie, Johnson and Johnson, Sanofi, Merck, Teva, Direct Biologics, Tr1x, Boehringer Ingelheim, Bristol Myers Squibb, Pfizer, Prometheus Biosciences, Takeda Pharmaceuticals, Roche Genentech, Eli Lilly, AstraZeneca, Spyre and Agomab, has received consulting fees from Johnson and Johnson, Abbvie, Merck, Sobi, Celltrion, Fresenius Kabi, Asahi Kasei Pharma, Sandoz and CorEvitas, LLC and has served on the board of the Srategic Alliance for Intercultural Advocacy in GI.

Introduction Asthma is a multifactorial disease influenced by genetic and environmental factors, including diet. The gut microbiome contributes to airway inflammation via the gut-lung axis, partly through production of short chain fatty acids (SCFAs) from bacterial fermentation of dietary fiber. We hypothesized that dietary fiber supplementation could modulate the gut microbiome and increase SCFAs in children with asthma. Methods This is a double-blind, placebo-controlled trial of children who were randomized to consume 12 g of soluble corn fiber (SCF) as a supplement to their usual daily diet (50% the recommended daily fiber intake) or placebo for 4–6 weeks ( clinicaltrials.gov NCT03673618). Dietary surveys, asthma symptom questionnaires, fecal, blood and nasal samples were collected before and after the intervention period to quantify fiber intake, asthma control, nasal and gut microbiome, and serum short chain fatty acids (SCFAs). Results Of the 20 children enrolled, 15 completed the intervention with an average adherence rate of 83%. SCFA concentrations and gut microbiome changes varied by individual and treatment group. No significant differences in gut or nasal alpha or beta diversity were observed between groups post-intervention. However, differential abundance analysis showed a trend toward increased Bifidobacterium in the SCF group compared to placebo (ANCOM-BC p = 0.0004, FDR q = 0.073). Discussion Supplementation of 50% of recommended daily fiber intake had minimal impact on asthma symptoms, the microbiome, or SCFA levels. Future studies should consider higher fiber doses, different fiber types, or targeting individuals with low baseline fiber intake to account for observed variability in microbiome and SCFA responses. Clinical Trial Registration https://clinicaltrials.gov/study/NCT03673618 , identifier NCT03673618.

399 Background: The standard of care for resectable GEA adenocarcinomas is perioperative chemotherapy with the FLOT (fluorouracil, leucovorin, oxaliplatin, docetaxel) regimen. Recent studies investigating the addition of checkpoint inhibitors (CPIs) to perioperative chemotherapy have shown mixed results. An NMA can leverage both direct and indirect comparisons to evaluate the relative efficacies of available regimens in this setting. Methods: MEDLINE, EMBASE, Scopus, Web of Science and CENTRAL were searched until August 27th, 2025. Eligible studies included phase 3 randomized trials evaluating perioperative or neoadjuvant chemotherapy +/- CPIs ± radiation in resectable GEA. The primary outcomes were disease-free survival (DFS) and overall survival (OS). Hazard ratios and 95% confidence intervals (CIs) were estimated using a frequentist NMA framework. Results: Fifteen trials including 8072 patients were analyzed. For DFS, perioperative durvalumab + FLOT (dFLOT) ranked highest (P-score = 0.99), followed by FLOT (P-score = 0.84) (HR for dFLOT vs. FLOT was 0.71, 95% CI 0.58-0.86). dFLOT also ranked higher than perioperative pembrolizumab + cisplatin and fluorouracil/capecitabine (KN-585), though this comparison was not statistically significant (HR 0.65, 95% CI 0.40-1.04). Compared with CROSS, dFLOT showed superior DFS (HR of 0.48, 95% CI 0.36-0.63). For OS, dFLOT ranked the highest (P-score=0.95) and was superior to CROSS (HR 0.57, 95% CI 0.42-0.77). While dFLOT appeared favorable versus FLOT (HR 0.78, 95% CI 0.62-0.98), this finding was primarily driven by MATTERHORN, which did not meet its prespecified OS significance boundary (P = 0.03 vs threshold P < 0.0001), and the proportional hazards assumption was violated. Similarly, no significant OS difference was observed between dFLOT and the KN-585 arms (HR 0.75, 95% CI 0.45-1.23). Conclusions: In this NMA, perioperative FLOT remained the benchmark regimen for resectable GEA. dFLOT has shown promising early results, ranking the highest for DFS and showing favorable, but not statistically definitive OS trends in comparison to FLOT. Importantly, the network enabled indirect comparisons not tested in head-to-head trials, demonstrating that dFLOT ranked above pembrolizumab+CF/CX (KN-585) without reaching statistical significance, and also outperformed CROSS. However, these findings should be interpreted with caution, as they are primarily driven MATTERHORN data in which OS did not cross the prespecified threshold and proportional hazards assumptions were violated. Perioperative immunotherapy combinations appear promising, but final MATTERHORN results and further confirmatory studies are needed before dFLOT can be considered as a new standard of care.

Understanding the evolution of clinical tools and models of care is fundamental to advancing the field of epilepsy. The 2025 American Epilepsy Society Annual Course examined the expanding spectrum of epilepsy care through the integration of multispecialty collaboration, innovative diagnostic modalities, and surgical and nonsurgical therapeutic interventions. The course underscored significant global advancements in epilepsy research and practice. This comprehensive review synthesizes key educational insights from the program, offering a critical perspective on the ongoing transformation of epilepsy care.

This study proposes a novel two-dimensional Empirical Mode Decomposition (2D EMD)-based deep learning framework to enhance model performance in multi-class image classification tasks and potential early detection of diseases in healthcare using medical imaging. To validate this approach, we apply it to gastrointestinal (GI) endoscopic image classification using the publicly available Kvasir dataset, which contains eight GI image classes with 1000 images each. The proposed 2D EMD-based design procedure decomposes images into a full set of intrinsic mode functions (IMFs) to enhance image features beneficial for AI model development. Integrating 2D EMD into a deep learning pipeline, we evaluate its impact on four popular models (ResNet152, VGG19bn, MobileNetV3L, and SwinTransformerV2S). The results demonstrate that subtracting IMFs from the original image consistently improves accuracy, F1-score, and AUC for all models. The study reveals a notable enhancement in model performance, with an approximately 9% increase in accuracy compared to counterparts without EMD integration for ResNet152. Similarly, there is an increase of around 18% for VGG19L, 3% for MobileNetV3L, and 8% for SwinTransformerV2. Additionally, explainable AI (XAI) techniques, such as Grad-CAM, illustrate that the model focuses on GI regions for predictions. This study highlights the efficacy of 2D EMD in enhancing deep learning model performance for GI image classification, with potential applications in other domains.

PURPOSE To compare patient-reported and clinical outcomes between radical cystectomy (RC) and bladder-sparing therapy (BST) in patients with recurrent high-grade non–muscle-invasive bladder cancer (NMIBC). PATIENTS AND METHODS This pragmatic, prospective observational cohort study was designed with patients, who selected and prioritized outcomes. Eligible adults were candidates for both RC or BST, had previous induction Bacillus Calmette-Guérin (BCG), and received their last treatment within 12 months. The primary outcome was the EORTC-QLQ-C30 physical function scale at 12 months. Secondary outcomes included other EORTC-QLQ-C30 scales, depression, anxiety, bladder cancer–specific quality of life (QOL), financial burden, and cancer-specific outcomes. Targeted maximum likelihood estimation (TMLE) was used to calculate average treatment effect (ATE) estimates between arms. Inverse probability weighted risk ratios (wRR) were calculated using quasi-Poisson regression. RESULTS Of 570 participants (mean age 71.4 years; 21% female), 371 selected BST and 199 selected RC. Physical function was significantly worse in the RC arm at 3 months; by 9 months, there was no difference between arms, and at 12 months, physical function did not differ (ATE, 0.9; 95% CI, –0.6 to 2.4; P = .22). RC was associated with better emotional function, generic health-related QOL, and financial burden, and lower depression and anxiety, while BST was associated with better bowel and sexual health. Cancer-specific survival was 99% for BST versus 96% for RC (wRR, 0.99; 95% CI, 0.97 to 1.01). RC was associated with a higher risk of adverse events and serious adverse events, including a 90-day mortality rate of 2.5%. CONCLUSION Most patient-prioritized outcomes were similar or better among participants who chose RC compared with BST. These findings support the continued role of RC in managing recurrent high-grade NMIBC.

Abstract Introduction: Elranatamab, a BCMA-CD3 bispecific antibody, has shown efficacy in relapsed multiple myeloma (MM), but real-world data on its safety and effectiveness are limited. Methods: We conducted a retrospective, multi-center study of patients (pts) treated with commercial elranatamab from 8/2023–3/2025 at 9 U.S. academic centers. Logistic and Cox regression were used for binary and time-to-event outcomes, respectively. Multivariable analysis (MVA) adjusted for prior lines of therapy (LOTs), baseline Hgb (per g/dL), and LDH (per 100 U/L) as continuous variables; and for BCMA exposure, extramedullary disease (EMD; extraosseous soft tissue lesions), and ECOG ≥2 as binary variables. Results: Of 130 pts, median age was 71 yrs (range 39–95); 57% were female, 82% white, 13% black, and 35% had ECOG ≥2 (11% ≥3). Median LOTs was 6; 91% were triple-class refractory, 49% penta-refractory, 49% BCMA-exposed (median 15.5 mo [IQR 11.8–20.5] since last exposure), and 49% had prior anti-BCMA CAR-T. Most recent BCMA exposures included: CAR-T (84%), TCE (9.4%), and ADC (6.3%). Only 22% met MagnetisMM-3 cohort A eligibility (which excluded BCMA-exposed pts). High-risk cytogenetics (del(17p), t(4;14), t(14;16), or amp(1q)) were present in 44% (25%, 13%, 6.3%, and 7.9%, respectively). EMD was seen in 22%. Median treatment duration was 4.0 mo (95% CI 2.93–6.3) overall and 7.9 mo (95% CI 5.83–NA) with ≥VGPR. Discontinuation due to toxicity or non-relapse mortality occurred in 12% but was significantly lower among those receiving IVIg (5% vs. 17%, p=0.031); IVIg was given in 47%. The overall response rate (ORR) was 65%, including ≥VGPR in 46% and ≥CR in 36%, consistent with MagnetisMM-3 (ORR 61%, ≥CR 35%; Lesokhin et al. Nat Med. 2023). After median follow-up of 7.5 mo, median PFS was 4.3 mo (95% CI 3.4–11.3), OS was 14.6 mo (95% CI 8.6–NA), and DOR was 12.2 mo (95% CI 6.1–NA). In contrast, MagnetisMM-3 (Prince et al., ASH 2024) reported median PFS and OS of 17.2 and 24.6 mo, respectively, with DOR not reached despite 28.4 mo of follow-up. In univariate analysis, ECOG ≥2 was associated with lower ORR (45% vs. 71%; OR 0.34, 95% CI 0.16–0.73, p=0.006), shorter OS (4.3 mo vs. NA; HR 2.41, 95% CI 1.33–4.35, p=0.004), and shorter PFS (1.7 vs. 6.5 mo; HR 1.77, 95% CI 1.09–2.87, p=0.020). Prior BCMA-directed therapy was linked to reduced odds of ≥VGPR (OR 0.38, 95% CI 0.19–0.77, p=0.008) and ≥CR (OR 0.43, 95% CI 0.20–0.89, p=0.025). Higher baseline LDH was linked to shorter OS (HR 1.37, 95% CI 1.23–1.53, p&lt;0.001) and PFS (HR 1.31, 95% CI 1.18–1.44, p&lt;0.001). Higher baseline Hgb was associated with higher ORR (OR 1.46, 95% CI 1.20–1.81, p&lt;0.001) and ≥CR (OR 1.54, 95% CI 1.26–1.92, p&lt;0.001). Among BCMA-exposed pts, recent exposure (&lt;1 [n=15] vs. ≥1 yr [n=32]) was associated with shorter OS (4.1 mo vs. NA; HR 3.66, 95% CI 1.26–10.6, p=0.017). In MVA, higher baseline LDH remained independently associated with shorter OS (aHR 1.36, 95% CI 1.19–1.54, p&lt;0.001) and PFS (aHR 1.27, 95% CI 1.13–1.43, p&lt;0.001); higher Hgb with greater odds of ≥CR (aOR 1.44, 95% CI 1.14–1.85, p=0.003) and longer PFS (aHR 0.84, 95% CI 0.72–0.99, p=0.034); and BCMA exposure with lower odds of ≥CR (aOR 0.32, 95% CI 0.10–0.91, p=0.037). CRS occurred in 40% (grade ≥2 in 12.3%, grade 3 in 2.3%), and ICANS in 17% (grade ≥2 in 7.7%). These rates contrast with MagnetisMM-3 (no grade ≥3 CRS, 3.4% ICANS). ICANS risk was lower in BCMA-exposed pts (9.4% vs. 24%; OR 0.32, 95% CI 0.11–0.85, p=0.029), and decreased with more LOTs (OR 0.73, 95% CI 0.55–0.92, p=0.016) and higher Hgb (OR 0.71, 95% CI 0.52–0.94, p=0.023). Tocilizumab and steroids were used in 36% (treatment 28%, prophylaxis 9.2%) and 23%, respectively. Steroid use was less common in BCMA-exposed pts (11% vs. 34%; OR 0.23, 95% CI 0.08–0.60, p=0.004) and declined with more LOTs (OR 0.68, 95% CI 0.52–0.85, p=0.002). Infections occurred in 40% of the cohort, more common in pts with CrCl &lt;40 mL/min (59% vs. 36%; HR 2.58, 95% CI 1.02–6.80, p=0.049). IVIg was linked to improved infection-free survival (HR 0.59, 95% CI 0.37–0.93, p=0.023). Conclusions: Elranatamab demonstrated meaningful activity in real-world relapsed MM, though PFS and OS were shorter than in MagnetisMM-3, likely reflecting an older, frailer population with higher disease burden. ICANS was more frequent than in MagnetisMM-3. Baseline anemia and elevated LDH, markers of poor marrow reserve and higher disease burden, were strongly linked to worse outcomes.

Abstract Introduction: Targeted therapy yields deep and durable response in histiocytic neoplasms.However, relapse rate following interruption is high at 75-77%, with a median time to relapse 6-9 months in previous studies. Outcomes after discontinuation in those who have already achieved a durable response are not well understood and are the focus of this study. Methods: We performed a multicenter retrospective study, including 4 US centers, including patients with histiocytic disorders treated with BRAF inhibitor (BRAFi), MEK inhibitor (MEKi), or combination BRAF/MEKi, and whose therapy was interrupted after ≥12 months of therapy following a best response of partial (PR) or complete response (CR). Progression-free survival (PFS) and overall survival (OS) were analyzed with Kaplan-Meier method. Cox regression was performed to identify clinical and molecular factors that are associated with PFS. Results: 26 patients were included (median age 55 [range 12-72]; male 53.8%; Caucasian 69.2%). Most predominant histology was Erdheim-Chester Disease (ECD) (n=15, 57.5%), followed by mixed histiocytosis (n=5, 19.2%). Rosai-Dorfman Disease (RDD) (n=4, 15.4%), and Langerhans Cell Histiocytosis (LCH) (n=2, 7.7%). All had BRAF V600E analysis and 10 (38.5%) were positive. 19 patients underwent additional molecular testing; alternative mutations identified included MAP2K1/2 (n=6, 23.1%), NRAS (n=1, 3.8%), RAF1 (n=1, 3.8%), ASXL1 (n=1, 3.8%), and SRSF2 (n=1, 3.8%). Targeted therapy was given as frontline therapy (n=8, 30.8%) or in the relapsed refractory setting (n=18, 69.2%) with median 1 prior line of therapy (range 0-7). Targeted therapies include BRAFi (n=5, 19.2%; 2 dabrafenib, 3 vemurafenib), MEKi (n=17, 65.4%; 14 cobimetinib, 3 trametinib), and BRAF/MEKi (n=4, 15.4%; 3 dabrafenib/trametinib, 1 vemurafenib/cobimetinib). PR and CR occurred in 8 (30.8%) and 18 (69.2%) patients, respectively. The median duration of treatment was 32 months (range 13-60) (12-24 months: 9 [34.6%]; 24-36 months: 7 [26.9%]; &gt;36 months: 10 [38.5%]). Median time from initiation of targeted therapy to best response was 6 months (&lt;6 months: 14 [53.8%]; 6-12 months: 5 [19.2%]; &gt;12 months: 7 [26.9%]). Median duration from best response to drug discontinuation was 19 months (12-24 months: 14 [53.8%]; 24-36 months: 7 [26.9%]; &gt;36 months: 5[19.2%]). Reasons for drug discontinuation include toxicity (n=8, 30.8%), patient preference (n=13, 50.0%), cost prohibition (n=1, 3.8%), and other critical medical conditions (n= 4,15.4%). Eleven patients (42.3%) experienced disease progression after discontinuation of targeted therapy, 5 patients progressed within 6 months. Systemic and CNS progression were captured by PET/CT and MRI brain, respectively. At median follow-up of 33.0 months (95%CI 24.3-47.1), median PFS, defined by time from targeted therapy discontinuation to progression or death, was 29 months (95% confidence interval [CI] not estimable). Median OS was not reached. In Cox regression model, BRAF V600E mutation (hazard ratio [HR] 4.16, 95% CI 1.10-15.70, p 0.036) and CNS involvement (HR 4.64, 95% CI 1.21-17.67, p 0.025) were associated with inferior PFS. MEKi containing regimen trended toward improved PFS (HR 0.35, 95%CI 0.10-1.21, p 0.097). There was no difference in PFS when assessing demographics, histology, prior therapies, best response to targeted therapy, treatment duration, or time from best response to discontinuation. Of the 11 patients with progression, 9 were re-challenged with targeted therapy (7 switched class), 2 did not receive next line therapy (1 transitioned to hospice and passed from progression, 1 has pending evaluation for next line therapy). Of 6 with response assessments, all recaptured response (1 CR, 5 PR), and none had progressed by data cutoff. Conclusions: In patients with histiocytic neoplasm and prior durable response to targeted therapy, ~40% experienced disease progression after treatment discontinuation. BRAF V600E mutation and CNS disease are associated with inferior PFS, suggesting these subgroups may not be appropriate for limited duration of treatment. Novel approaches are needed in these high-risk patients.